A commonly practiced non-destructive technique, confocal microscopy, allows for the imaging of thin planes of focus without background noise interference. These images can be stacked to form a three dimensional model of a subject, but is restricted to sub-millimeter regimes and translucent or transparent matter. Another newly developed method of laser tomography described in M. P. Echlin et al., “A New Femtosecond Laser-Based Tomography Technique for Multiphase Materials,” Adv. Mater., 23:2339-2342 (2011), uses a beam oriented perpendicularly to the imaged surface, and removes material at known rates. This method is used for metals and would not work well for samples with varying consistency, density, porosity, and absorption coefficients, as the penetration depth would vary depending on these characteristics.
Other means to image specimens include a microtome method and X-ray microtomography. A microtome (similar in concept to a meat slicer) is used to cut thin sections of a specimen embedded in a paraffin wax substrate which then are transferred to a solution bath to remove excess substrate, then transferred to an imaging device, aligned, acquired, and digitally stacked into a 3D model. X-ray tomography is nondestructive and uses virtual slices taken by a thin X-ray beam and computationally reconstructed. However, this method does not yield compositional data or color, and instead produces a map of the materials' X-ray absorptivity (related to a density profile).